Thanks for your reply. I'm referring this link https://docs.openstack.org/mitaka/admin-guide/compute-images-instances.html to understand about root disk. In this it is saying root disk will come from compute node. What is the location of root disk on compute node? If I want to keep all my vms on shared storage . How to configure it ? Or If I want to keep all my vms on cinder volume. What will be the configuration for it on nova and cinder? On Thu, 11 Jul 2019, 15:24 Eugen Block, <eblock@nde.ag> wrote:
Hi,
it's always glance that serves the images, it just depends on how you decide to create the instance, ephemeral or persistent disks. You can find more information about storage concepts in [1].
If I'm not completely wrong, since Newton release the default in the Horizon settings is to create an instance from volume, so it would be a persistent disk managed by cinder (the volume persists after the instance has been deleted, this is also configurable). The image is downloaded from glance into a volume on your volume server.
If you change the Horizon behavior or if you launch an instance from the cli you'd get an ephemeral disk by nova, depending on your storage backend this would be a local copy of the image on the compute node(s) or something related in your storage backend, e.g. an rbd object in ceph.
Does this clear it up a bit?
Regards, Eugen
[1]
https://docs.openstack.org/arch-design/design-storage/design-storage-concept...
Zitat von Jyoti Dahiwele <jyotishri403@gmail.com>:
Dear Team,
Please clear me my following doubts. When I use image from source option and mini flavor to create an instace, from which storage pool instance will get root disk ? From cinder or glance?